Final answer:
DNase would inhibit transformation, transduction, and conjugation in a genetic transfer experiment because it degrades DNA (Option D).
Step-by-step explanation:
If DNase was added during a genetic transfer experiment, transformation, transduction, and conjugation would all be inhibited. DNase is an enzyme that degrades DNA, so it would break down any DNA present in the experiment. Transformation refers to the uptake of DNA by a prokaryotic cell, transduction involves the transfer of genetic material by a bacteriophage, and conjugation is the transfer of DNA between prokaryotic cells via a pilus.
Since all of these modes of genetic transfer involve the transfer of DNA, they would be inhibited by the presence of DNase. Hence, D is the correct option.